Excitation Voltage¶
The CoilExcitationVoltage excitation option applies a voltage across the coil.
The voltage can be a constant value or a time-dependent function (for a
time-transient simulation).
The current flowing through the coil is determined by the coil's resistance, the back electromotive force and the applied voltage according to Ohm's law:
\[
I = \frac{1}{R} \left( U - \mathcal{EMF} \right)
\]
where \(I\) [A] is the current through the coil, \(U\) [V] is the applied voltage, \(R\) [\(\Omega\)] is the coil resistance, and \(\mathcal{EMF}\) [V] is the back electromotive force induced by the changing magnetic field.
The back EMF (electromotive force) induced in the coil is given by Faraday's law of induction:
\[
\mathcal{EMF} = -\frac{\mathrm{d} \Psi}{\mathrm{d}t}
\]
where \(\Psi\) is the magnetic flux linkage through the coil, and \(t\) is time.